• Journal of the Korean Chemical Society
• /
• v.37 no.3
• /
• pp.335-343
• /
• 1993

The maximum absorption wavelengths of charge-transfer complexes of naphthalene, ${\alpha}-and{\beta}-methyl$ naphthalene and 1,2-, 2,3-and 2,6-dimethyl naphthalene with chloranil have been measured with a UV spectrophotometer in ethylene chloride, methylene chloride, and chloroform at 10, 15, 20, and 25$^{\circ}C$. This absorption band was interpreted as the charge transfer band of a 1 : 1 molecular complex, and the maximum absorption wavelength was changed as a function of solvent and temperature. Their formation constants (K$_f$) were decreased with the polarity of solvent and the increase of temperature. Thus, the influences of solvent and temperature on the formation constant have been discussed as consideration of thermodynamic properties, and the electronic and steric effects of electron donors on formation constant have been also discussed.

• Journal of the Korean Chemical Society
• /
• v.37 no.2
• /
• pp.265-268
• /
• 1993

• Proceedings of the PSK Conference
• /
• 2000.10a
• /
• pp.278.2-278.2
• /
• 2000

• Journal of the Korean Chemical Society
• /
• v.25 no.4
• /
• pp.228-235
• /
• 1981

Ultraviolet spectrophotometric investigation were carried out on the systems of pyridine, ${\beta}$-picoline and 3,5-lutidine with iodine in carbon tetrachloride. The results reveal the formation of one to one molecular complexes of the type, $C_5H_5N{\cdot}I_2$, ${\beta}-C_5H_4(CH_3)N{\cdot}I_2$ and 3,5-$C_5H_3(CH_3)_2N{\cdot}I_2$. The equrilibrium constants of complexes were obtained in consideration of that absorption maxima have the blue shift with the increasing temperatures according to the formation of the charge transfer complexes. The thermodynamic parameters, ${\Delta}H$, ${\Delta}G$ and ${\Delta}S$ for the formation of the charge transfer complexes were calculated from these values. These results indicated that the relative stabilities of the pyridine, ${\beta}$-picoline and 3,5-lutidine complexes with iodine increase in the order, pyridine < ${\beta}$-picoline < 3,5-lutidine. These results were supposed to be the influence resulted from increase of electron density by the positive inductive effect and the dipole moment of the steric hindrance effect. And this results were compared and discussed with polymethylbenzene-iodine CT-complexes.

• 한국신재생에너지학회:학술대회논문집
• /
• 2010.06a
• /
• pp.89.2-89.2
• /
• 2010

The dye-sensitized solar cell (DSSC) is a device for the conversion of visible light into electricity, based on the sensitization of wide bandgap semiconductors. The performance of the cell mainly depends on a dye used as sensitizer. The absorption spectrum of the dye and the anchorage of the dye to the surface of $TiO_2$ are important parameters determining the efficiency of the cell. Generally, transition metal coordination compounds(ruthenium polypyridyl complexes) are used as the effective sensitizers, due to their intense charge-transfer absorption in the whole visible range and highly efficient metal-to ligand charge transfer. However, ruthenium polypyridyl complexes contain a heavy metal, which is undesirable from point of view of the environmental aspects. Moreover, the process to synthesize the complexes is complicated and costly. Alternatively, organic dyes can be used for the same purpose with an acceptable efficiency. The advantages of organic dyes include their availability and low cost. We designed and synthesized a series of organic sensitizers containing long wavelength absorption-chromophores for the dye sensitized solar cell. The DSSC composed of Blue-chromophores for the sensitization absorbed long wavelength region which is different also applied into the dye-cocktail (mixing) system. The photovoltaic property of DSSCs organic long wavelength absorption-chromophores were measured and evaluated by comparison with that of individual chromophores.

• 한국신재생에너지학회:학술대회논문집
• /
• 2011.05a
• /
• pp.118.1-118.1
• /
• 2011

The dye-sensitized solar cell (DSSC) is a device for the conversion of visible light into electricity, based on the sensitization of wide bandgap semiconductors. The performance of the cell mainly depends on a dye used as sensitizer. The absorption spectrum of the dye and the anchorage of the dye to the surface of TiO2 are important parameters determining the efficiency of the cell. Generally, transition metal coordination compounds(ruthenium polypyridyl complexes) are used as the effective sensitizers, due to their intense charge-transfer absorption in the whole visible range and highly efficient metal-to ligand charge transfer. However, ruthenium polypyridyl complexes contain a heavy metal, which is undesirable from point of view of the environmental aspects. Moreover, the process to synthesize the complexes is complicated and costly. Alternatively, organic dyes can be used for the same purpose with an acceptable efficiency. The advantages of organic dyes include their availability and low cost. We designed and synthesized a series of organic sensitizers containing long wavelength absorption-chromophores for the dye sensitized solar cell. The DSSC composed of Blue-chromophores for the sensitization absorbed long wavelength region which is different also applied into the dye-cocktail (mixing) system. The photovoltaic property of DSSCs organic long wavelength absorption-chromophores were measured and evaluated by comparison with that of individual chromophores.

• Journal of the Korean Chemical Society
• /
• v.19 no.2
• /
• pp.73-84
• /
• 1975

The effect of pressures and temperatures on the stabilities of the toluene-iodine charge transfer complex have been investigated through ultraviolet spectrophotometric measurements in n-hexane. The stabilities of complexes were measured at $25~60{\circ}C$ under 1~1,200 bars. The equilibrium constant of the complex was increased with pressure and decreased with temperature raising. The absorption coefficient was increased with both pressure and temperature. Changes of volume, enthalpy, free energy and entropy for the formation of complexes were obtained from the equilibrium constants. The red-shift observed a higher pressure, the blue-shift at a higher temperature and the relation between pressure and oscillator strength were discussed by means of thermodynamic functions.

• Journal of the Korean Chemical Society
• /
• v.26 no.6
• /
• pp.363-368
• /
• 1982

Ultraviolet spectrophotometric investigations were carried out on the systems of pyridine with iodine, iodine monobromide and iodine monochloride in carbon tetrachloride. The results reveal the formation of the one to one molecular complexes of the type, $C_5H_5N{\cdot}I_2$, $ C_5H_5$N{\cdot}IBr and $ C_5H_5N{\cdot}ICl$. Considering ${\lambda}_max$ according to the formation of charge transfer complexes has the blue shift with the increasing temperatures$25, 40, 60^{\circ}C$ the equilibrium constants K and molar absorptivities $\varepsilon$ of complexes were obtained. From these values, the thermodynamic parameters ${\Delta}H$, ${\Delta}G$ and ${\Delta}S$ for the formation of the above charge transfer complexes were obtained. These results indicate that the relative stabilities of iodine, iodine monobromide and iodine monochloride complexes with pyridine increase in the order, $ C_5H_5N{\cdot}I_2$ < $ C_5H_5N{\cdot}IBr$ <$ C_5H_5N{\cdot}ICl$. This may be a measure of relative acidity of halogen and interhalogen toward pyridine and can be explained by the polarizabilities of electron acceptors and the difference of electronegativities of halogen atoms.

• Journal of the Korean Chemical Society
• /
• v.34 no.4
• /
• pp.331-339
• /
• 1990

It has been studied that relations between electronic structure and anti-tumor activity by variation of amine group in cis-diamminedichloroplatinum (Ⅱ) complexes. We were also interested in these Pt (Ⅱ) complexes interaction with 1-methylcytosine of DNA base and the electronic structure of these complexes in order to understand the mechanism of the metal-nucleobases interaction. The results showed that net charge of center metal in Pt complexes effect anti-tumor activity. The mechanisgm of the bonding between metal and ligands largely based on charge transfer from ligand to metal atom. Furthermore, the established molecular orbitals showed that metal 6p-orbitals played an important role in the bonding scheme for the interactions between platinum (Ⅱ) complexes and 1-methylcytosine. We also found that the stronger Pt-N3 bonding strength became, the better anti-tumor agents were.

• Bulletin of the Korean Chemical Society
• /
• v.19 no.9
• /
• pp.897-906
• /
• 1998

A new synthesis has been developed for 1-thia-4,7-diazacyclononane and the complexation behavior of a particular derivative has been explored. The pentadentate ligand 4,7-bis(2-pyridylmethyl)-l-thia-4,7-diazacyclononane ([9]$N_2SPY_2$) and its iron(Ⅱ) and manganese(Ⅱ) complexes were prepared and characterized. Magnetic moments of 5.17 and 5.90 μB respectively, indicate that the iron(Ⅱ) and manganese(Ⅱ) complexes are high spin. Charge transfer transitions (d-π*) occur for [Fe(Ⅱ)([9]$N_2SPY_2)(X)]^{n+}$at 27027, 25000, and 24390 cm-1 for X=$H_2O$, Cl-, and OH-, respectively. In acetonitrile solution, the cyclic voltammogram of the manganese(Ⅱ) complex exhibits a redox couple at 0.92 V vs. NHE while the redox potentials for [Fe(Il)([9]$N_2SPY_2)(X)]^{n+}$ are 0.70, 0.66, and 0.37 V vs. NHE for X=$H_2O$, Cl-, and OH-, respectively. The d-π* charge transfer energy and Fe(Ⅱ)/Fe(Ⅲ) redox potential for [Fe(Ⅱ)([9]$N_2SPY_2)(X)]^{n+}$ increase in the same order: $H_2O>Cl^- >OH^-$. The crystal structures of the iron(Ⅱ) and manganese(Ⅱ) complexes reveal that the metal ions are sixcoordinate, binding to four nitrogen atoms and a sulfur atom from the pentadentate ligand, as well as a chloride anion, with the chloride and sulfur atoms in cis positions. The two metals have similar coordination geometries, which are closer to trigonal prismatic than octahedral. In both iron and manganese complexes, the M-N($sp_3$) trans to Cl- is 0.07 Å longer than the one cis to Cl- , and M-N($sp^2$) trans to S is 0.05 longer than the one cis to S atom.